This is a security and bugfix release. ## Security If a client connects using MQTT v5, will a Will message that has MQTT v5 properties attached, and the very first Will property is one of `content-type`, `correlation-data`, `payload-format-indicator`, or `response-topic`, then at the point the client disconnects, the broker will attempt to read from freed memory, resulting in a possible crash. ## Broker - Fix memory access after free, leading to possible crash, when v5 client with Will message disconnects, where the Will message has as its first property one of `content-type`, `correlation-data`, `payload-format-indicator`, or `response-topic`. Closes [#1244]. - Fix build for `WITH_TLS=no`. Closes [#1250]. - Fix Will message not allowing `user-property` properties. - Fix broker originated messages (e.g. `$SYS/broker/version`) not being published when `check_retain_source` set to true. Closes [#1245]. - Fix `$SYS/broker/version` being incorrectly expired after 60 seconds. Closes [#1245]. ## Library - Fix crash after client has been unable to connect to a broker. This occurs when the client is exiting and is part of the final library cleanup routine. Closes [#1246]. ## Clients - Fix `-L` url parsing. Closes [#1248]. [#1244]: https://github.com/eclipse/mosquitto/issues/1244 [#1245]: https://github.com/eclipse/mosquitto/issues/1245 [#1246]: https://github.com/eclipse/mosquitto/issues/1246 [#1250]: https://github.com/eclipse/mosquitto/issues/1250